Which of the following wavelengths in $\mathring{A}$ represents 'hard' $X$-rays?

The essential distinction between $X$-rays and $\gamma$-rays is that:

The Compton effect is associated with

The intensity of $X$-rays from a Coolidge tube is plotted against wavelength as shown in the figure. The minimum wavelength found is ${\lambda _c}$ and the wavelength of the ${K_\alpha }$ line is ${\lambda _k}$. As the accelerating voltage is increased:

If the cathode-anode potential difference in an $X$-ray tube is $10^5 V$,then the maximum energy of an $X$-ray photon can be:

The typical wavelength of $X$-ray is